The need to characterize complex organic compounds for biotechnology applications, such as protein sequencing, has placed stringent requirements on the development of characterization tools. Recent developments in cluster ion formation and ion bombardment desorption theory suggest that cluster ion bombardment of complex molecules may provide a mechanism to characterize complex species and significantly improve the ability to sequence proteins. The specific aims are to: 1) develop a supersonic nozzle to produce homonuclear atom cluster densities up to 10/15cm-3; 2) modify a time-of-flight ion extraction source to accomodate the laser ionization of atom clusters; 3) evaluate the cluster ion densities and size distributions using a modified time-of-flight mass spectrometer; 4) demonstrate the feasibility of desorbing high molecular weight organic molecules. The successful completion of these aims is expected to result in a versatile cluster ion source to desorb neutral and ionized high molecular weight organic compounds, such as peptides and peptide chains. The molecules or molecular ions may be further characterized using existing mass spectrometric and laser technology. Commercial potential includes the development for sale of a simplified atom cluster ion desorption source (ACIDS) and the development of an applications market for analytical characterization services for protein sequencing.